Separable connector



Nov. 28, 1944. w.- H. HUNTER SEPARABLE CONNECTOR Filed Jan. 20, 1943 2 Sheets-Sheet J;

for mounting between a pair tures and for conducting fluid.

convenience of manufacture, simplicity of con Patented Nov.

SEPABABLE CONNECTOR Willson H. Hunter, Akron, Ohio, assignor to The B. F. Goodrich Compan corporation of New York y, New York, N. Y.,-a

Application January 20, 1943, Serial No. 472,972

16 claims. (or. 244-134) This invention relates to separable connectors and especially to plug and receptacle assemblies of adjacent struc- Objects of the invention are to provide for effectively joining a pair of structures in an improved quick-detachable manner, to provide for externally interconnecting the structures while providing for the flow of fluid, to provide for fluidtightness of .the connection while permitting angular misalignment and movement, to provide for the smooth flow of fluid under pressure and for resisting accidental disengagement of the separable connector assembly, and to provide for struction, and convenience and reliability of operation and assembly;

More specific objects of my invention are to airovide meansfor facilitating the installation of inflatable'protective covering for preventing ti e accumulation of ice upon an airfoil. to provide for externally connecting the covering in a separable self-sealing manner to a source of fluid within the airfoil while withstanding pressure, suction, and low temperature conditions, to provide'for preventing air flow from'within the airfoil to space between the airfoil and ,the protective covering,'and to provide for permitting flow offluid while the protective covering is in. a collapsed condition. y

. These and otherobjects and advantages of the invention will be apparent from the following description. v

In the accompanying drawings; which form a part of this specification, and in which like numerals are employed to designate like parts throughout the same,

Fig. 1 is a view in elevation showing a separable fluid-conducting connector assembly secured to an airfoil and to an inflatable protective covering; and constructed in'accordance with and embodying the invention, parts being broken away and in section and being in a disengaged condition,

Fi '2-is a view like Fig. 1 but showing the connector assembly in an engaged condition,

Fig. 3 is a view showing a plug and a receptacle for theconnector assembly of Fig. 1, parts being I broken away and in section,

Fig. i is 'aview in elevation-showing a modified construction of the connector assembly, parts heing-broken away and in section, M Fig. 5 is a view in elevation showing a further modification of the connector assembly, parts he- I broken away-and in section. and

Fig. Bis a view looking to the right of the strucsection.

ture of Fig. 5, parts being broken away and in In the illustrative embodiment of the invention shown in Figs. 1 to 30! the drawings, a plug II) v and 'a receptacle or socket II for a separable fluid-conducting connector assembly I 2 are attached to the margins of respective apertures I3 and It in an inflatable protective covering I5 and an airfoil .IB, such, for example, as an airplane wing. The inflatable covering may be used for preventing the accumulation of ice in a manner, for example, as is disclosed in Geer Patent No. 1,998,809. The plug I0 and the receptacle II are made, preferably, ofa-resilient rubber or other rubber-like material, molded and vulcanized; although other suitable plastic, or even non-plastic materials such as metal may in some cases be used. I

The plug III comprises an annular body having a'flanged end I! and abore I! of substantially uniform diameter for conducting a fluid, such as air, through the annular body into an inflatable tube I9 in the protective covering I5. The flanged end I1 is tapered in section and may have a suitable reinforcement Ill, such as a woven fabric, as shown especially in Fig. 3, for maintaining the circular shape of the flanged end [1 despite the tendency of the margin of the aperture I 3 in the protective covering It to distort under tension induced by inflation of the tube I9.

It is desirable to secure the plug III at the flanged end I] to the protective covering I5, in the manner shown in Figs. 1 and 2, by a suitableadhesive such as rubber cement; however, the

flanged end may instead be adhered to the exterior surface of the covering I5 adjacent the condition. By virtue of the shape of the flanged end H,

which permits its conformance to the surface 01' the airplane wing I 6 and permits a snug flt with the receptacle II, the protective covering I5 may be installed upon the airplane wing It at the leading edge, as shown in Fig. 2, in a tightly stretched condition and free of objectionable air pockets between the covering I5 and the wing I6 surface and free of objectionable protuberances which cause a loss of aerodynamic efllciency of the wing.

The annular body of the plug III has a substantially hemispherical or generally bulbous end portion 22 opposite the flanged end I! and an in substantiall hemispherical end to the termediate reduced portion 253 tapering from the end. The annular body is proportioned such that a it will not buckle under axial compression which may be caused by frictional engagementwith the receptacle ll.

The intermediate reduced portion 23 permits angular misalignment with the receptacle H; while the substantially hemispherical end portion 22 permits sealing contact with'the receptacle for all conditions of misalignment, the thicker wall at the end portion 22 resisting undue compression and insuring a tight seal in the region of the bulbous end 22 during engagement of the plug iii and the receptacle l.

mulation of ice upon the plug it) including the ribbed For completing the connection of the inflatable protective covering it in a separable manner to the source of fluid, the receptacle M is mounted in an aperture u in the airfoil id or airplane wing, as shown in Figs. 1 and 2. Preferably, a metal reinforcing plate 2%, which may be of aluminum alloy, is attached, as by riveting, to the margin of the aperture to in a wing skin it'd of aluminum alloy, for example, and the plate 213 has an aperture with a countersunk margin 26 for retaining the receptacle it in position for engaging theplug l8 and for providing space for the flanged end ll of the plug.

The receptacle or socket ii of resilient rubberlike material has a generally irusto-conical body and ahollow cylindrical end portion is for connecting to a fluid conduit 29, such, for example, as metal or other tubing of suitably stifi materiai, which is interconnected with a source of supply of fluid, such as air under pressure. The

. body ill has; preferably, a substantially concentric frusto-conical bore 30 terminating in a bore Sta of substantially uniform diameter at the cylindrical end portion 28, the latter bore 80a being substantially the same diameter as that of the bore 58 of the plug it! and as the internal diameter of the fluid conduit 2% for providing for smooth flow o't fluid through the separable connector assembly I2. However, the bore 30 may be of substantially uniform diameter and of a diameter suitable for providing for elastically gripping the bulbous'end 22 of the plug Ill. The fluid conduit 29 registers against a shoulder portion 3| at the region of the bore 30a and is retained in position by a clamping ring 34 and desirably by a. suitable adhesive like rubber cement.

As shown in Fig. 3, the body 21 has a sealing lip 32 at the end opposite the cylindrical end portion 28 for contacting the countersunk margin 26 of the aperture 25 in the-plate 24, the sealing lip being substantially normal to the axis of the ,bodyJl as molded and being flexed, as' shown by dotted lines, when the receptacle H is mounted on the plate 24 to exert sealing pressure against the margin 26. The sealing lip 32 may, if desired, be adhered to the margin 26 by a suitable adhesive like rubber cement A recess 32 asoaeoa tions oi angular misalignment and internal fluid pressure. Also, when under a condition of suction, the body 2! tends to diminish in diameter by virtue of the elasticity of the rubber-like material, thus increasing the effectiveness orthe elastic gripping and sealing action of the wall upon the plug id.

In ,the operation of the separable connector assembly M2 for conducting fluid to the inflatable protective covering ii for preventing the accuairplane wing 88, the bleeder element ii is attached to the protective covering as described hereinabove and the receptacle H is inserted in the aperture it in the wing IS, The receptacle H is mounted upon the margin26 of the aperture 25 in the plate 2B-by seating the margin 26 in the recess 33 and by flexing and desirably adhering the sealing lip 32 into' contact with the margin 26, whereby a depression 35 is provided, as shown especially in Fig. 2, for receiving the flanged end ll of the plug Ill and for movement and angular misalignment of thelplug'with respect to the bore 38 of the receptacle ii. the fluid conduit 29 is connected to the cylindrical end portion 2% of the receptacle in a fluidtight manner, using the clamping vring St for this purpose. However, the fluid conduit 29 may be secured to the receptacle it before the receptacle is mounted in place as described hereinabove.

Furthermore, the leakage of air from within the wing it to the space between the protective covering it and the wing skin Ida through the aperture 25 is prevented efiectively by the sealing lip 32 and the recess 33 being in contact with tion shown in Fig. 2, the resilient walloi the generally frusto-conical body 21 elastically gripping and sealing with the substantially hemispherical end 22 of the plug despite movement and angular misalignment which may occur during the alternate inflation and deflation or durmg the installation of the protective covering I5 upon the airplane wing I6. For greater ease of insertion of the plug, the bore 30 of the receptacle ll may be lubricated with deflocculated graphite, glycerine, wax, or other suitable lubricants, which are not harmful to the rubber-like material of the plug and receptacle. I The bore 18 of the plug I0 is in register with v the bor 300. and the opening in the fluid conduit 28 during engagement of the plu'gand receptacle adjacent the lip 32 provides for seating the margin 26, which together with the sealing contact of the lip 82 with the margin 26 due to flexure of the lip 32 prevents air leakage from within the airplane wing It to the space between the protective covering 15 and the wing skin lia thereby eflectively preventing objectionable bulging of the protective covering.

The wall of the generally l'rusto-conlcal body 21, as shown in Figs. 1 and 3, is of an intemal diameter and a thickness such as to provide for elastically gripping and sealing with the generally bulbous end 22 or the plug In under 6139 con ifor facilitating smooth flow of fluid through the the plug fits into'the depression 35 adjacent the sealing lip 32 of the receptacle, which permits movement of the plug and permits the protective covering l5 to conform to the wing skin lid without objectionable protuberance. any tendency of the plug It to slide out'of engagement with th receptacle I I, when fluid under pressure is admitted to the connector assembly l2 or during the operation-of the resisted by the pressure of the fluid within the tube l9 acting upon the area of the flangdend tion of the elastic gripping is substantially no reducaction upon the plug I II under varied temperature conditions of operaof theplug; There Then ,The flanged end I! or protective covering, is

tion encountered, for example, during flight; inasmuch as the thermal coefiicient of expansion and contraction of the rubber-like material of the plug and of the receptacle is substantially identical.

In the modified construction shown in Fig. 4, the separable fluid-conducting connector assembly comprising a plug 40'and a receptacle on socket 4| is arranged in an operative manner with the inflatable protective covering I5 and the airfoil I6 or airplane wing. The plug 40 has an annular body 42, preferably of resilient rubber or other rubber-like material and has a cylindrical element 43 of stiff material, such as metalor a suitable plastic material, and includes a bore 44 of substantially uniform diameter extending therethrough. It is desirable to unite the body 42 and the element 43 as by molding and vulcanizing in which case the element 43 is provided with a flange 45 for embedding in the body 42 of rubber-like material.

The annular body 42 has a flanged end 46 tapered in section for attaching at the margin 41 of an aperture 48 in the covering l5, the flanged end 46 having a plurality of spaced-apart grooves 49 in a face thereof adjacent the wall I5a of the covering I5 opposite the wall |5b having the aper .ture 4B, the grooves extending outwardly, preferably radially, from the bore 44 for assuring flow of fluid while the covering I5 is in a deflated condition. The flanged end 46 is secured to the inner surface of the wall I5b' of the inflatable covering 5 as by a suitable adhesive such as rubber cement, and conforms, by virtue 'of its shape, to the surface of the airplane wing 6 without objectionable bulging of the covering IS. The

cylindrical element-43 of the plug 46 engages with the receptacle 4| in a separable manner.

The receptacle 4| of resilient rubber-like material has, desirably, a generally frusto-conical body 50 and a hollow cylindrical end portion 5| for connecting to a fluid conduit 29 in a manner as described hereinabove for Fig. 1' assembly. The body 56 has a sealing lip 52 for contacting the countersunk margin 26 of the aperture 25, the sealing lip 52 like the lip 32 being substantially normal to the axis of the body 50 as molded and being flexed, when the receptacle 4| is mounted in place in the aperture 25 in th airplane wing l6, to exert sealing pressure against the margin 26. The sealing lip 52 may be adhered in place, if desired, by a suitable adhesive such as rubber cement. A recess 53 adjacent the lip 52 provides for seating the margin 26, to co-act with the sealing lip 52 in preventing leakage of air from within the airplane wing. I6 in the manner described hereinabove for the assembly shown in Fig. 1.

The body 50 has a bore 54 including an inwardly extending portion 54a extending from the flanged end 52 and terminating in a bore 54b of substantially uniform diameter at the hollow cylindrical end; portion 5|, the latter bore 54b being substantially the same diameter. as that of the bore 44 of the plug 40 and as the internal diameter of the fluid conduit 29 for obtaining smooth flow of fluid through the separable connector assembly. The bore 54 at the inwardly extending portion 54a, is of a diameter less than the diameter of the cylindrical element 43 and the wall of the body 50 is of suitable thickness to provide for elastically gripping and sealing with the cylindrical element 43 of the plug 40 at the portion 54a.

With the arrangement shown in Fig. 4, angular misalignment and movement of the plug 40 is permitted while smooth flow of fluid is facilitated through the connector assembly. The flanged end 46 of the plug is disposed in the depression 55 and conforms to the curvature of the airplane wing I6 without undue bulging of the protective covering I5. Also, any tendency of the plug 46 to slide out of engagement with the receptacle 4| during the operation of the inflatable covering I5 is resisted by the pressure of the fluid within the tube I9 acting upon the area of the flanged end 46 to maintain the plug 40 in its engaged position.

The arrangement shown in Figs. 5 and 6 is like that shown in Fig. 1 in many aspects but is especially useful for facilitating the installation of a protective covering having one or more pairs of adjacent inflatable tubes 6| 'and 621 which are inflated, desirably, substantially simultaneously. The separable, fluid-conducting connectorassembly comprises a plug 63 of resilient; rubber or other rubber-like material and a receptacle or socket 64 having a body 65 of rubber or other rubber-like material and, preferably, a hollow cylindrical end portion 66 of still material, such, for example, as plastic or metal tubing.

The plug 63 comprises an annular body having a pair of spaced-apart flanges 61 and 68 at one end and a bore 69 of substantially uniform diameter extending partly therethrough from the opposite end. The flange 68 is generally rounded and tapered in section while the flange 61 is tapered in section, the flanges 61 and 68 being preferably annular in shape and being joined by a pair of spaced-apart, substantially diametrically disposed partitioning ribs 10 for providing for side apertures TI and 12 between the flanges for communication between the bore 69 or fluid conduit and the inflatable tubes 6| and 62.

The respective portions of the flanges 6'! and 68 at each side of the partitioning ribs 16 are secured to the exterior surfaces of the margins 13a and 13b and 14a and 74b of apertures 15 and 16 in the tubes 6| and 62 by a suitable adhesive such as rubber cement; and ribbed bleeder elements TI and I8 are similarly secured, desirably, in the tubes 6| and 62 at the region between the flanges 61 and 68 for assuring flow of fluid while the tubes 6| and 62 are in a collapsed condition. The ribs of the bleeder elements 11 and 18 are disposed, preferably, in a radially, outwardly extending manner, but may be disposed in any other suitable manner whereby flow of fluid is permitted despite a collapsed condition of the tubes 6| and 62.

The annular body of the plug 63 has a subs'tantially hemispherical or generally bulbous end portion 19 opposite the flanges 61 and 68 and an intermediate reduced portion 60 tapering from the substantially hemispherical end to the flanges. The annular body is proportioned such that it will not buckle under axial compression which may be caused by frictional engagement with the receptacle 64.

The body 65 of the receptacle 64 is generally frusto-conical in shape and has a sealing lip 8| for contacting .the margin 26 of the aperture 25 in the plate 24, the sealing lip being, if desired, adhered to the plate as by a rubber cement,. andhas a recess82 adjacent the lip 8| for seating the margin 26. In the manner as described above for Fig. 1, leakageof air, from within the airplane wing |6,to the space between the protective covering 66 and the wing skin |6a is prevented effectively whereby the aerodynamic gneaaea eficiency =rna'intained by: the elimination oi undue bulgingoithe protective covering til.

The body '65 has a bore of substantially uniflange-of resilient rubber liisev material for con- I tasting the: margin: of said aperture,': and said formdiameter extending'iromthe sealingilip at and'terminating in a bore til of substantially-uni= form lesser diameter for registering with the bore d9 of'the plug 63. The bore 83 is or alesser diameter than the diameter of the generally bulbous end" ldz ior providing for elastically gripping the plug -63 .in engagement with the receptacle body having a bore extending from said flexible rlange' ioryreceiving said, plugin sealing relationftherewitm-caid borebeingat least as large at the flanged end as at position -.-inwardly there'- of'to-accommodateentry of saldplug and the wall of said bore' being re'slicnt forxel'as'tically gripping said plug. r

'55. The'rnctal tubingfib has an. mternalfdiameter substantially equivalent to .the bore-6t and has, preferably, a flanged end" 55a for .niolding and vulcanizing'the metaltubing St integralwith the body'tl at'the regionlfof the'bore $3 5.. A

fluid conduit 85, such as flexible hose, is attached to the metal tubing 66 by a suitable clamping ring at and may be adhered in place, if desired, by a suitable adhesive such as rubber cement;

The plug 63 and receptacle 6d are engaged in the manner described hereinabove for Figs. 1 to 6. "A socket 'for holding a plug and adapted ,icrmounting in an aperture in a wall, saidisocket comprisingabody having atone end a sealing [lip for contacting the margin of said aperture and a recess adacent said lip for seating said marthe pl'ug'fid with the receptacle 65, the flange G? is disposedadjace'nt thesealing lip 8|,in'the space 87 for providing for asmcothly curved exterior surface 'of the protective. covering Ell for promoting smooth flow of air over thawing it. Thus the aerodynamic emciency of "the airfoil is substantially maintained.

Variations may bemade without departing from the scope of the invention'as it is defined in the following claims.

I claim:

l. A plug for conducting fluid and for separably engaging a socket, said plug comprising a body having a fluid conduit therein and including an outwardly bulged, elastic portion of greater wall thickness than adjacent portions, of said body for elastically engaging in said socket in sealing relation therewith.

2. A plug for conducting fluid and for separably engaging a socket, said plug comprising a body having a fluid conduit'of. substantially uniform bore extending therethrough and including a flexible attaching flange at one end and an elastic portion of generally bulbous shape of greater wall thickness than adjacent portions of said body at the opposite end for elastically engaging insaid socket in sealing relation therewith and having a reduced portion intermediate said elastic portion and said flange.

3. A plug for separably engaging in asocket and conducting fluid therethrough into-an inflatable container, said plug comprising a body of resilient rubber-like-materhl including a fluid conduit therein and including a. pair of spacedgin, and said body having a bore extending :fromsaid lip for admitting said'plug and having an elastic portion intermediate the ends o'f said body for elastically gripping the plug, said bore being of gradually decreasing size at positions inwardly of the lip and to accommodate entry of said plug.

7. A socket for a fluid-conducting plug and adapted'for ,mounting in an aperture in a wall, said socket comprising an annularbody of elastic material including a sealing lip at one end for'contacting the margin of said aperture, said annular body having abore extending from said sealing lip and terminating in an opening of substantially uniform diameter for registering with a fluid-conduit in said plug, the wall of said bore. being elastic for gripping :the plug in sealing relation therewith, said bore being at least as large at the lip end as at positions inwardly thereof to accommodate entryof said plug.

8. A socket for a'fluid-conducting plug and adapted. for mounting in an aperture in a wall, said socket comprising a generally irusto-conical body of resilient rubber-like material and including a cylindrical end portion for connecting to a fluid conduit, said body having a sealing lip at the end opposite said cylindricalportion for contacting the margin of said aperture and having substantially uniform a bore extending from said lip and terminating at said cylindrical end portion in an opening of diameter for registering with a fluid conduit in said plug, said bore being oi gradually decreasing-size at positionsinwardly of the lip end to accommodate entry of said plug and the wall of said bore being resilient for elastically gripping said plug.

9. An inflatable container and plug assembly' forseparably engaginga socket for conducting fluidto said container. said assembly comprising apart flanges at an end thereof for attaching at a margin in the inflatable container with a portion of said container between said flanges.-

4. A plug for separably engaging a socket, said plug comprising a body of resilient rubber-like material having a substantially uniform bore therein'extending from anend thereof and ineluding a resiliently deformable portion of genan inflatable container and a plug, said plug comprising a body of resilient rubber-likematerial including a fluid conduit of substantially uniform bore extending therethrough and a flanged end for attaching' at the marginof an aperture in said container, said body having a resilient end portion .of generally "bulbous shape of greater wall thickness than adjacent portions of said body opposite the flanged'end and being of a size greater than at least a part of theinner diameter of said socket for elastically and separably engaging saidsocket in sealing relation therewith and said body having a reduced portion intermediate the bulbous end portion and said flanged end, and means at said flanged end for assuring flow-of fluid while said inflatable container is in a collapsed condition.

10. An inflatable container and plug assembly for separably engaging .a socket for conducting fluid to said container, said assembly comprising an inflatable container and a. plug, said plug comprising a body of resilient rubber-like material including a fluid conduit extending therethrough and having. a flanged end for attaching at the margin of an aperture in said container and at the inner surface of the wall of said container, said flanged end having a plurality of ing a body including a fluid conduit of substantially uniform bore therein and a resilient portion of greater wall thickness "than adjacent portions of said body, and ,said body including a flexible flange at anendthereof for attaching at a margin in one of said structures, and a socket hav ing a body including a flexible flange at one end for contacting the margin of an aperture in the other said structure, said body of said socket havmg a bore extending therethrough from said end for receiving said plug in separable and sealing relation, said bore of said socket being at least as large at the flanged end as at positions inwardly thereof to accommodate entry of said plug and the wall of the latter said bore being resilient for elastically gripping said resilient portion of said plug.

12. A separable, fluid-conducting connector assembly for mounting between a pair of adjacent structures, said assembly comprising a plug having .a body of resilient rubber-like material including a fluid conduit therein and including a pair of spaced-apart flanges at an end thereof for attaching at a margin in one of said structures with a portion of said margin between said flanges, said body having a side aperture .between said flanges for communication between said fluid conduit and said structure, and a socket having a body including a flexible flange at one end for contacting the margin of an aperture in the other said structure, said body of said socket having a bore extending therethrough from said end for receiving said plug in separable and sealing relation, said bore being at least as large at the flanged end as at positions inwardly thereof to accommodate entry of said plug and the wall of .said bore being resilient for elastically gripping said plug.

13. A separable, fluid-conducting connector assembly for mounting between a pair of adjacent structures, said assembly comprising a plug hav-' ing a resilient-body of rubber-like material including a fluid conduitof substantially uniform bore therein and a flanged end for attaching at the margin of an aperture in one of vsaid-structures and said plug having an end portion of ly uniform diameter and including a flanged end flanged end of said socket to accommodate entry of said plug and the wall of said bore being resilient for elastically ipping said pl 14. In a separable connector assembly for conducting fluid from within an-airfoil to an inflatable protective covering on the airfoil, in oombination, an elastic plug having a bore of substantialior attaching at the margin of'an aperture in said covering, said plug having a generally bulbous end portion opposite the flanged end and an intermediate reduced portion; an elastic receptacle for receiving said plug and including a sealing lip at one end for contacting the margin of an aperture in said airfoil and a recess adjacent said sealing lip for seating the latter said margin, said receptacle having a counterslmk bore extending from the sealing lip and terminating at the opposite end of the receptacle in an opening of substantially uniform diameter for registering with the bore of said plug, the bore of said receptacle being of a, diameter less than the plug for elastically gripping the generally bulbous end of said plug; and means for assuring the flow of fluid from said plug while the protective covering is in a deflated condition.

15. In a separable connector assembly for conducting fluid from within an airfoil to an inflatable protective covering on the airfoil, in combination, a plug of resilient rubber-like material having a bore of substantially uniform diameter therein and including a pair of spaced-apart flanges at an end thereof for attaching at the margin of an aperture in said covering and said plug having a side aperture between said flanges for communication between said bore and said covering and including a substantially hemispherical end portion opposite the flanged end and an intermediate reduced portion tapering from said substantially hemispherical portion to the flanged end; a receptacle of resilient rubberlike material for receiving said plug said refor connecting'to a fluid conduit, said frustoconical body having a countersunk bore in communication with and terminating'at said substantially cylindrical end portion in an opening of substantially uniform diameter for registering withv the bore of said plug, the wall of said. frusto-conical body being of a diameter less than said plug for elastically gripping the plug at said substantially hemispherical end portion, and

said frusto-conical body having a sealing lip oppomte said substantially cylindrical endportion for contacting the margin of an' aperture in said vairfoil and having a recess adjacent saidlip for seating the latter said margin;--and a ribbed bleeder element disposed between said flanges of said plug for permitting flowof fluid, while said i protective covering is in a collapsed condition.

generally bulbous shape-opposite said flanged end,

said end portion being of greater; wallthickness than adjacent portions of said body, and a socket having a resilient body of rubber-like material including a flange at one end for contacting the margin of an aperture in the other said struc-.

decreasing size at positions inwardly of the 16. In a separable connector assembly for conv ducting fluid from within an airfoil to an inflatable protective covering on the airfoil, in combination, a plug including an annularbody of resilient rubber-like material and a tubular element of stiff material and having a bore ofsubstantially uniform diameter extending through said annular body and said tubular element, said annular body including aflanged end opposite said cylindrical element for attaching at the'margin of an aperture in said covering and at the inner surface-of the wall ofsaid covering, ld

flanged end having a plurality of spaced-apart -I v 2,368,592 grooves in a face opposite said aperture and portion for connecting to a fluid conduit, said within saidcovering tor assuring flow of fluid rrusto-conical body-having a bore including an while said covering is in acollapsed condition, inwardly extending portion in communication said grooves extending outwardly from said bore, with and terminating at said substantially cylin and a receptacle of re ent rubber-like material 5 drical end portion in an opening: of substantially for receiving said plug and including a sealing unifomdiameter for registering with the borelip at one end forcontacting the margin of an of said plug,'tl1e wall of said inwardly extending aperture insaid airfoil anda recess adjacent said portion being of a width less than said tubular sealing lip for seating the latter said margin, element of said-plug for elastically gripping said said receptacle comprising a generally virustotubular element inseparable and sealing relation.

"'1' 5, ON" HULQTER.

conical body and a substantially cylindrical end CERTIFICATE OF CORRECTION. Patent No. 2,565,592. I November 28, 19M.

WILLSON H. HUNTER.

It is hereb; certified that error appears in the printed specificationof the above numbered patent requiring correction as'follows Page 5", first column, line 8; for receptacle on" read -r eceptacle or--'; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 27th day of February, A. D. 1915.

LeslieFrazer (Seal) Acting Commissioner of Patents. 

